Technical breakdown of C5 model year changes?

[Brett]

I am very close to finally getting my Corvette.

The model years I am interested in are '98-'00.

Can anyone tell me what production changes, besides the obvious ones, happened throughout the C5 years? I checked through the CAC model center, and it lists some, but not the more technical ones.

For example, I heard from someone that the '99-'00's have "smaller injectors and smog restrictions" compared the the '97-'98's. Is this true? Does it affect performance?

Is there anything else like this I should know about from year to year?

Thanks!

 

[dmd]

Brett,

I used to own an early '98 and I became intimately familiar with early-C5 quirks in the six years I owned it. Here's what I know:


'97-98 had 28lb injectors. Single-rail fuel line system introduced for '99 models dropped to 26lb injectors.

'97-98 had the first-gen PCV system, redesigned and relocated for '99-02 to try to address the recirculation of oil into the intake through the PCV. (I don't think it fixed it.)

The JL4 active handling was not available for all '98 cars, it was introduced mid-year around January. They also changed the airbags to deploy less forcefully due to a change in DOT regulations at the same mid-year '98 changeover.

Revised accessory tensioner to eliminate a squeaky one in '00.

Revised the generator pulley and the tensioner again to eliminate a rumbling noise on automatics in '01.

'98-'02 6-speed cars had the piston ring problem that resulted in high oil consumption. It was not fixed in production with the new rings until '03.

'97-99 headlight door plugs tended to fly off randomly. Fixed in '00 with a new-design plug and bezel.

'97-'98 cars had noisy fuel pumps, which was corrected in '99.

'97-'99 cars developed radial stress fractures on the rotors, and calipers twisted under hard braking causing diagonal pad wear in severe duty (racing). Not sure when this was fixed.

EGR was eliminated in '01.

'97-'98 engines had a very thin cylinder liner that could tolerate only .005" overbore, which is essentially a one-time service hone.


This is a really cool TSB, nice to know that GM actually cares about people with this problem and fixed it:

http://www.corvetteactioncenter.com...2+or+3-2+Downshift+and+Subsequent+2-3+Upshift

Anyway, there's a lot more of the intricate technical changes to ALL LS1 cars available here:

http://ls1tech.com/forums/showthread.php?t=213148

Dave D

 

[Brett]

Great stuff! This is exactly what I am talking about. Thank you.

I thought it was the '01's that were the big oil burners of the C5 generation due to the revision of the LS1?

 

[dmd]

All 6-speed LS1's back to '97 burned a lot of oil, but I wouldn't be surprised if the '01s were the worst.

 

[Remo]

01' Oil Burners

GM got the oil consumption problem under control by November of 2001. Cars produced after that were good. Mine was built in late January of 2001 and doesn't lose any oil between changes. It was a concern to me because the Chevy dealer I bought mine from always had a couple of the ealier cars in their shop for the rebuild corrections.
Remo:cool

 

[Mr. Lucky]

• '98 was the last year of 28lb injectors and return-style fuel system (i.e., two hoses passing thru the fuel rail covers versus the single one on later years). It doesn't make much difference until you get above ~500rwhp, then the return style is better. 1999 thru 2000 had 26lb injectors; GM teturned to using 28lb in 2001.
• 1998 was the first year active handling was available
• "2nd generation" Active Handling introduced in 2001
• 2001 and later had 85mm MAF w/ integrated IAT sensor, versus 76mm w/ discrete IAT sensor in earlier years

 

[skitch]

Thats great info, I would like some info like that on the C4's.I already know some of the Quirks on the 90 models.

 

[Best Vette Yet]

All 6-speed LS1's back to '97 burned a lot of oil, but I wouldn't be surprised if the '01s were the worst.

I had a 2001 vette, she used 1 quart every 800 miles. I was told by the GM Rep that I was hammering the car and that I was driving her around in 4th gear to keep my RPM above 4000. All this was real dumb as my DIC showed average gas consumption of 27.8 mpg as my vette was used specifically on the highway. Dealing with the GM Rep was the most humiliating experience I have ever had as in his mind, I was guilty before my trial. The dealership insisted that I produced gas receipts to check mileage and consumption. After transmission, oil problems (the motor developed a knock after 2800 miles) and 18 months of sheer heartache, I traded her for a new 2003. I have never looked back...my 2003 NEVER uses any oil and the transmission is flawless. Just for the records, I have not changed my driving habits I pity the unfortunate person who purchased my 2001 but I am relieved to know that I was not the only person who had oil consumption problems.......empathy is real.

 

[leftyvette]

I should not jinx myself, but I have a 2000 that does not use oil. Was there something from the 1990s and the 2001 that was different from the 2000 model? Maybe my time is coming!!!

 

[Brett]

I should not jinx myself, but I have a 2000 that does not use oil. Was there something from the 1990s and the 2001 that was different from the 2000 model? Maybe my time is coming!!!

The 2001's are generally the problem year in regards to this issue. In 2001 the LS1 was tweaked to 350 hp/380tq or something like that, and it screwed up something with the ring clearance.

Your 2000 should be a-ok.

 

[leftyvette]

Good to hear that the 2000 should be ok. I reread some of the earlier posts after I posted my message. It seems like the 6-speeds are the problems. Mine is an automatic. I learn something on this forum everyday!!!

 

[DRTH VTR]

If I remember correctly, oil consumption was associated with certain driving habits. Running high RPM's under light load was a lot of the problem. Mostly, people with automatics will not drive like that.

 

[Best Vette Yet]

The 2001's are generally the problem year in regards to this issue. In 2001 the LS1 was tweaked to 350 hp/380tq or something like that, and it screwed up something with the ring clearance.

Your 2000 should be a-ok.

I believe it had something to do with 1st oil ring being chromed ie it was harder to seat in the piston sleeve thus resulting in "blo-by". GM solved this by changing out the 1st oil ring only on each piston. The rest of original rings from the factory install were not touched. I believe this "blo-by" occurred above 3500 RPM. :BOWC4C5 would be able to give us the correct answer as he is an absolute guru.....I take everything he says to heart....he has never been wrong.

 

[dmd]

I had the ring-job done on mine and it did not solve the problem. My car is now out of warranty even though it only has 21,000 miles, and I live 2000 miles from the dealer that did the service 4 years ago. How can I petition for this to be fixed again?

 

[Best Vette Yet]

I had the ring-job done on mine and it did not solve the problem. My car is now out of warranty even though it only has 21,000 miles, and I live 2000 miles from the dealer that did the service 4 years ago. How can I petition for this to be fixed again?

If it was done 4 years ago, there is no way that you will get any luck from the dealership. Most of them are there just to make money, few are there for customer satisfaction. Sorry this did not work for you. You may try contacting the GM Reps and make a noise there, but from experience, you will be banging your head against a brick wall. :bash
Solution would be just to enjoy your Vette, check your oil level regularly and drive her like you stole her. Another solution would be to get a new sub assembly and retrofit....expensive but would serve you for the rest of the vehicles life.

 

[Brett]

GM got the oil consumption problem under control by November of 2001. Cars produced after that were good. Remo:cool

'98-'02 6-speed cars had the piston ring problem that resulted in high oil consumption. It was not fixed in production with the new rings until '03.

Ok, so I have been told, in the same thread, two different stories concerning when the ring problem was fixed. There is a huge difference between November of '01 and '03! What one is correct?